OOAK Table Tennis Forum

Regarding the low bounce of seamed Chinese polyballs, I think the main problem is ITTF has already sold out the rights to these inferior ball makers at the expense of superior products available from Nittaku Japan and to a lesser extent, seamless ball makers. Because of this, it will be extremely difficult for local tournament directors NOT to use inferior seamed Chinese polyballs in order to loyally follow the ITTF.

So I'm still trying to figure out if:

1. The balls are too rushed and thus unready

or

2. The final state of plastic balls is inferior

These two seem mutually exclusive.

3. Superior balls aren't adopted by ITTF for their most important tournaments.

*DHS won the bid (if there were any open bidding at all) so we are stuck with balls that give low bounces instead of Nittaku Japan balls or seamless balls that are much closer to the old celluloid ball.

I ask the same questions but stipulate that they apply mainly to the seamed plastic balls currently made in China. The seamed ones I have gotten from Japan (Nittaku Premium 40+) are really good, I think everybody will be quite satisfied with them (except for prices and for the moment, availability). I don't really have too many complaints about the seamless balls ITTF has approved either. The issues about those plastic balls, to the extent that there are any, come from their size, but ITTF is mandating that by setting a strict cutoff at 40.00 mm (which in practice means balls you buy now are going to be about 0.4 mm larger than most celluloids we have been using). The effect of size on ball play is a feature, not a bug. Their materials and roundness seem quite good. So, it is not impossible to make a decent ball out of plastic. However DHS has not yet figured out how to do it. Some people think DF is better, but they are still not good enough IMHO. I will try some of those again this week to renew my familiarity with them.

My best guess from making a lot of different kinds of measurements of my own is that the only way they could be considered ready is if ITTF lets them slide under the specs come January 2016. It will depend on what they do then. I am hoping they will be very strict on disallowing balls that are bouncing too low.

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Butterfly Viscaria Black tag
2.2 mm Nexy Karis M on FH and BH

I'm still convinced that I get more spin on the seamed compared to the seamless balls, but this is hard to measure of course...

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I think that the XSF balls are on average slightly larger in diameter than seamless Chinese balls, that might be why. But the difference is pretty small. I don't mind that as much as I mind the low bounce of seamed balls, and bear in mind my game is pretty much based on topspin.

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Butterfly Viscaria Black tag
2.2 mm Nexy Karis M on FH and BH

According to this USATT official's blog, DHS40+ is not the sole ball brand to be adopted for major international events for the season to come 2014 -2016.

http://blog.kaginism.com/

Tournament directors in domestic competitions have always been required to state the brand and color of the ball that will be used. Now they are also asked to clearly state whether it will be a celluloid or non-celluloid ball. But if you're not sure which ball your upcoming tournament will be using, you need to ask them.

If you play internationally, the ball that will be used is pretty much predetermined:
•ITTF Junior Circuit events prior to the Youth Olympic Games - Butterfly *** celluloid, white
•Youth Olympic Games - DHS *** celluloid, white

•ITTF Junior Circuit events after the Youth Olympic Games - Butterfly 40+ *** non-celluloid, white
•ITTF World Tour events - DHS 40+ *** non-celluloid, white
•North American Championships - Double Fish 40+ *** non-celluloid, white
•World Championships - Butterfly 40+ *** non-celluloid, almost certainly white
• Europian Teams' Champs - Nittaku 40+ *** non celluloid, white

Igor, all you need to know is all ITTF World Tour events use DHS polyballs and all World Youth events use DHS-made Butterfly polyballs. Regular Nittuku 40+ is also made by DHS. The North American Championships is a Mickey Mouse event that no one cares what ball it uses. So with the exception of the European Teams that used the made-in-Japan Nittaku Premiums that no one can buy yet, ALL major ITTF events use DHS polyballs.

Slightly = 0.5cm; the whole tolerance range is no larger than 1.0cm downwards from the middle. The "problem" I meant is just this: Tables do not allow for standardized bounce measuring, because the surface age influences the bounce height. Therefore you cannot transfer the exact difference from lab to table or from one table to another.
The lab test for these balls was done in the 2nd half of January 2014, so that the balls were probably manufactured in the first two weeks of 2014.

Can you provide any comments on this thread where someone went to the trouble of replicating all the tests? viewtopic.php?f=6&t=26817

Given those results I suspect a significant portion of actual playing difference is attributable to surface friction, which does vary more between models with these new balls (esp against celluloid). Is there any reason why it's not measured/standardized by the ITTF considering the importance of spin in the sport?

As to #1, that person (Debater) has discussed his plan to produce those videos beforehand with me. We also talked about the issue of replicating ITTF lab tests with a different equipment a normal player or club official can afford or produce himself. At the end of this absolutely valuable discussion, we fully agreed on the two points in question:
1, testing equipment different to that in a lab will not produce exactly the same results, so the "troubles" cannot be avoided completely
2, this does no harm to a qualitative examination of the balls, so it is worth the effort to deal with the "troubles" and keep them as small as possible
To summarize it, to me as an ITTF official such a try is helpful and not a disturbance.

As to #2, one big reason through the years was to balance the need for tests and the time and cost for these. Costs will be broken down to the National Associations and ultimately to the clubs and their players (= you and me), so that one has to act responsibly with that. So the claim was, and still is, that the balls' properties are sufficiently described by the specifications in place. However, you are right that the use of a complete new material may change this situation: If the celluloid balls did not use the full range of tolerance, but plastic balls do, then this is probably perceived as "change of variation", although the "minimum requirements" did not change at all. Whether this becomes a big issue will depend heavily from the (professional) players' ongoing feedback. If so, then it will probably require additional specs to keep the variations narrow enough. And if so, there are a couple of ideas how to do it. Among these are durability, surface roughness - and friction.

For #1 I meant more along the lines of whether his results were consistent with yours.

For #2 I was wondering if the ITTF has looked into/attempted minor amendments like testing COR for more than one data point or simple friction measure with a weight + scale. Ie viewtopic.php?p=285428#p285428.

Thanks.

One thing I can add, Torsten. Debater has sent me his data and I have been doing some statistics on the outcomes. Many of these data show statistically significant differences between cellulloid and plastic, and the direction of the results would have to be the same as you would measure in Singapore. For example, the difference between celluloid and plastic in terms of bounce height is significant at 10-12 level (ten raised to the -12th power). I was impressed by the consistency of the data, with a mean difference of very nearly 10 cm between plastic and celluloid when dropped from 305 cm. The plastic ball is very consistent, and I would say consistently bad in this respect. The data on veer also show a significant difference in number of failures between plastic and celluloid (to the disadvantage of plastic relative to celluloid). Data from my own laboratory on weight (using a very accurate analytical balance) show that none of the Joola plastic balls are within the allowable range (coming January of 2016). I actually don't mind the weight when I play, personally I really dislike the bounce.

I think if you use all of the plastic balls in bounce height tests there will be some that are a bit higher than cellulloid (XSF), some very similar to celluloid (Nittaku Japan) and all of the Chinese seamed plastic balls below the allowable range, or at least at the very lowest end of it. Since that comprises the balls that are really the worst on the other criteria as well (weight, roundness, veer, and durability), it would be unfortunate if those were to become the standard. In my opinion, the Chinese seamed ball simply must be forced to improve!!! The other two factories seem to have succeeded in making a reasonable plastic ball, balls that I am quite happy to play with, so it is clearly not impossible.

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Butterfly Viscaria Black tag
2.2 mm Nexy Karis M on FH and BH

Hi Torsten, will the ITTF be publishing the results of these tests and if yes, when will they be published and where can we read them please?

Just wondering about something - 305cm is 10 feet, wouldn't the ball have reached terminal velocity way before it's half way down? If so, then the 10 foot drop would be equivalent to, say, a 5 foot drop (or whatever height you need to achieve terminal velocity in air), a 10cm (4 inch) difference is even WORSE than it looks (as a percentage of drop height).

I'll try some calculations tomorrow to figure out the height needed to achieve terminal velocity - time to look up Stoke's Law again...

Iskandar